[6] Castle's film credits include Dark Star where he played the beach ball alien, Major Payne, Dennis the Menace, The Last Starfighter, and Connors' War as a director.

In 1978, he played the iconic starring role of Michael Myers in the classic horror film Halloween, directed by former USC classmate John Carpenter,[7] and was paid 25 dollars a day.

[6] Castle wrote August Rush, a musical-drama directed by Kirsten Sheridan and starring Freddie Highmore, Jonathan Rhys-Meyers, Robin Williams, and Keri Russell, which was released in 2007.

[10][11] The announcement of Nick Castle's participation was widely reported as his retaking the role of Michael Myers he originated,[12] with stunt performer James Jude Courtney only doing additional work as the character.

[15] Castle won a Saturn Award for Best Writing for The Boy Who Could Fly, a Silver Raven (for Delivering Milo), a Grand Prize (for The Last Starfighter), a Bronze Gryphon, and a Gold Medal of the Regional Council.